From Infinite to Two Dimensions through the Functional Renormalization Group

Category: Scientific Highlights

Published in Physical Review Letters

ABSTRACT:

We present a novel scheme for an unbiased, nonperturbative treatment of strongly correlated fermions. The proposed approach combines two of the most successful many-body methods, the dynamical mean field theory and the functional renormalization group. Physically, this allows for a systematic inclusion of nonlocal correlations via the functional renormalization group flow equations, after the local correlations are taken into account nonperturbatively by the dynamical mean field theory. To demonstrate the feasibility of the approach, we present numerical results for the two-dimensional Hubbard model at half filling.

 

	Figure: Schematic illustration of the DMF2RG approach, showing the evolution of the Gaussian part G0 Λ of the action from DMFT to its exact expression for a two-dimensional system. The (truncated) flow equations for the self-energy ΣΛ and the two-particle vertex ΓΛ are explicitly given in terms of Feynman diagrams.

 

Taranto C., Andergassen S., Bauer J., Held K., Katanin A., Metzner W., Rohringer G., Toschi A. (2014), From Infinite to Two Dimensions through the Functional Renormalization Group, Phys. Rev. Lett. 112, 196402. DOI:10.1103/PhysRevLett.112.196402, pdf

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